1. Field of the Invention
The invention relates to a forming method and forming apparatus for forming, using a pressing and injection-molding multifunction die, metal-resin molded products, and a metal-resin molded product that is formed by the method or the apparatus described above. More specifically, the invention relates to a forming method and forming apparatus for forming, using a pressing and injection-molding multifunction die, metal-resin molded products, for example, connectors with terminal pins, in which one end portions of multiple metal terminal pins droop from one end of a resin chip and the other end portions of the multiple metal terminal pins, which extend from the other end of the resin chip, are bent in the direction perpendicular to the resin chip.
2. Description of the Related Art
According to an existing hoop forming technology, metal-resin molded products, which are formed by integrating metal with resin, are produced successively in a continuous forming process as shown in FIG. 4. In this continuous forming process, first, a metal plate M is pulled out of a supply reel L on which the metal plate M is wound. Then, the metal plate M is inserted into a press die of a press forming device P1, punch-pressed, and rolled up in a hoop manner in a zone A. Next, the punch-pressed metal plate M, which is in the form of semi-finished products at this stage, is inserted into an injection-molding die of a resin-molding device Q, and resin-molded portions are formed on predetermined portions of the metal plate M, whereby the metal plate M, which is in the form of semi-finished products at this stage, is integrated with the resin. The punch-pressed metal plate M integrated with the resin is rolled up in a hoop manner in a zone B. After that, the punch-pressed metal plate M with the resin is inserted into a press die of a press forming device P2 and pressed. Finally, finished metal-resin molded products are cut out from the metal plate M.
Japanese Examined Patent Application Publication No. 08-2557 (JP-B-08-2557) describes a technology related to an insert molding method and insert molding apparatus for processing metal and resin in an integrated fashion. According to the insert molding method, a metal insert member, which is supplied by continuous conveyance, is pressed, undergoes resin-molding, and is then cut at regular intervals, whereby insert molded products are successively produced. The metal insert member is pressed and cut at an opening/closing portion that is formed integrally with a molding die, used for resin molding, and that opens and closes in accordance with an opening/closing operation of the molding die.
In the insert molding apparatus according to JP-B-08-2557, the molding die, which opens and closes, is provided with a resin-molding portion. The resin-molding portion forms a resin-molded portion on the insert member, which is supplied by continuous conveyance from one side to the other side of the resin-molding portion. A pressing portion is provided at least at a position upstream of the resin-molding portion in the direction in which the insert member is conveyed, and a cutting portion is provided at a position downstream of the resin-molding portion in the direction in which the insert member is conveyed. In accordance with the opening/closing operation of the molding die, a resin-molded portion is formed on the insert member at a first predetermined position by the resin-molding portion, the insert member is pressed at a second predetermined position by the pressing portion, and the insert member is cut at a third predetermined position by the cutting portion at the same time. In this way, insert molded products that are pressed are successively produced by opening/closing the molding die and conveying the insert member.
However, in an insert molding method and insert molding apparatus according to related art, in order to convey semi-finished products, the metal plate needs to be conveyed with links (metal bridges) left in some portions of the metal plate. Therefore, the metal bridges need to be left in the metal plate until the final process. The presence of the metal bridges causes problems such as restriction on positions at which metal portions are bent and formation of steps in cutting surfaces that are formed after the metal bridges are cut off. According to the technology described in JP-B-08-2557, semi-finished products are connected to the metal plate by metal bridges, and the insert member is continuously delivered to the pressing portion, the resin-molding portion and the cutting portion sequentially, whereby the products are formed. The insert molding apparatus described in JP-B-08-2557 has other problems that the structure thereof is a considerably complicated and the apparatus is expensive.